"I wanted to let you know that, as my other obligations are beginning to take an inordinate amount of time, I have asked to step down as WMG's Board Chairman, effective January 31, 2012," the memo reads in part. "However, I will remain a director of the company and in that way, continue my association with Warner Music and its extraordinary people. It has been a unique and special privilege and honor for me to have worked alongside you. Thank you again for all the support, commitment and determination you have given to WMG and to me, as we worked together to transform our business."

"Today, I also write to thank Edgar for all that he's done for the company, and all that he will do in the years to come. His leadership, counsel and guidance have been-and will remain-invaluable. ... It was his vision in transforming WMG into a progressive, modern music company that made WMG so attractive to Access. Given that vision and his years of expertise in the industry, as a director at WMG, he will continue to be an important part of our leadership and I look forward to his many future contributions."

In addition to remaining on the WMG board of directors, Bronfman is also the general partner of Accretive, a private equity firm; the executive chairman of Global Thermostat, a company that develops technology to capture carbon dioxide from the atmosphere and other sources, while co-generating power; and chairman of Endeavor, a company that mentors entrepreneurs and helps them build companies.